Histamines are known to play a role in allergies and related allergic problems. The effects of histamines are controlled by the same G protein that is overly active in McCune-Albright syndrome. Thus, one could predict that patients with McCune-Albright may be at high risk for allergic problems. To date, no studies have documented any form of histamine excess or allergic difficulties in patients with McCune-Albright syndrome. However, the investigators have made the observation that a high percentage of their patients with MAS exhibit a range of allergic symptoms, from mild symptoms, to severe, life-threatening symptoms.